Forty-two million infants and young children worldwide were overweight or obese in 2013, according to the World Health Organization. A previous study published in Preventive Medicine suggested that parenting style – either a lack of attention or over controlling – was to blame, resulting to kids who couldn’t regulate their eating habits.

A recent study published in the journal Pediatric Obesity has found a simple but effective trick that could reverse this. It could help overweight children not only lose weight but also help them control their eating habits. The trick was to eat more slowly, chewing each bite for 30 seconds.

Bioengineers from the University of California collaborated with physicians from the National University of Mexico to find out if eating slowly had an effect on body weight. “Our method focuses on preventing weight gain,” said Dr. Ruy Perez-Tamayo. “It is simple, inexpensive and easy to follow.”

“The study’s goal was to minimize the amount of food that children ate before their stomachs finally told their brains that they’re no longer hungry—the so-called “satiety reflex.” That signal usually takes about 15 minutes to kick in. But in modern society, whole meals can be consumed in much less time,” said the release.

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Researchers monitored the eating habits of 54 Mexican children for a year to see if eating slowly made a difference to their body weight. They were divided into two groups: a compliant group that carried out a 30-second rule and a non-compliant group that didn’t. The two groups were also compared with a control group.

The 30-second rule was that each bit had to last 30 seconds. They had to chew their food for half a minute before moving on to the next bite. Researchers reasoned that eating slowly allowed the body time to tell the brain that it was full. The compliant group was given each a 30-second hourglass timer to help them along.

Results proved the rule effective. The compliant group’s weight reduced anywhere from 3.4 to 4.8% after a year. The non-compliant group increased in weight by 8.3 to 12.6% in the same time period. The control group’s weight also increased at 6.5 to 8.2%.

The good thing about the slow eating approach is that it’s easily sustainable for a long time unlike most diets that required you to alter what you eat, said study co-author Geert Schmid-Schonbein. “You can adopt this slow eating approach for yourself and keep it up for the rest of your life,” he said.

Being overweight can lead to serious health problems if escalated to obesity. Being obese is linked to having cancer (colon and prostate in men, and uterus and gall bladder in women), type 2 diabetes (increasingly seen in children too), heart disease and respiratory problems. It can also have damaging psychosocial effects. Read more on the dangers of childhood obesity in a Smart Parenting article here.